/**
 * 开发中，有无this并没有影响，有其他的方案解决
 * 但是会比较麻烦，编写代码不方便
 */
var obj = {
  name: "yz",
  sleeping: function() {
    console.log(this.name + " is sleeping")
  },
  learning: function() {
    console.log(this.name + " is learning")
  },
  smiling: function() {
    console.log(this.name + " is smiling")
  }
}
obj.sleeping()
obj.learning()
obj.smiling()
